() \(V_{\text{ij}}=\frac{2k}{x_{j}-x_{i}}\ln\left(\frac{\delta_{j}}{\delta_{i}}\right)+\frac{x_{i}+x_{j}}{2t}-\frac{y_{i}^{2}-y_{j}^{2}}{2t\left(x_{j}-x_{i}\right)}\text{\ \ .}\)